The Little Mermaid dwells in an underwater kingdom with her widowed father (the sea king or Mer-King), her dowager grandmother, and her five older sisters, each of whom had been born one year apart. When a mermaid turns fifteen, she is permitted to swim to the surface for the first time to glimpse the world above, and when the sisters become old enough, each of them visits the upper world one at a time every year. As each returns, the Little Mermaid...